Air filters are constructed for use in air handling and filtration devices, such as heating and cooling equipment for living or work spaces, or in other settings such as air handling equipment used for cooling electronic equipment. These systems typically utilize a fan or blower motor to generate forced air, so as to circulate air or to move air past particular components. To control the airborne dirt or contaminants that would otherwise be stirred in the air and circulated throughout the system or space that is in communication with the system, the fan usually is associated with an air filter that is located within the air flow path generated by the fan. Periodic cleaning or replacement of the air filter is necessary to achieve proper and efficient air flow, as well as to provide proper care and maintenance of the components of such air handling systems.
In air handling systems, it is common to locate an air filter in a plenum through which the forced air travels. Moreover, access for insertion of an air filter is usually provided by a slot formed in the plenum by an elongated opening in a wall of the plenum and supporting rails along the walls adjacent to the wall having the opening. The air filters then typically include a filter media mounted to and surrounded by a rigid four-sided frame that is sized to be slidingly received in a corresponding plenum slot. Thus, it is common to install an air filter by grasping the rigid outer frame and sliding the frame into a slot in a plenum of an air handling system. The air filter generally is removed by again engaging the rigid frame and withdrawing the air filter from the slot.